That will look up each mbox file under ~nirmala/mail. If there is
an mbox file called e.g. ~nirmala/mail/work, aoximport creates a
mailbox called /users/nirmala/old/work and copies the mail there.

Subdirectories are supported. Empty mailboxes aren't imported.

File/directory names have to be ASCII or UTF-8. If a name uses
e.g. ISO-8859-1, aoximport will import the mail, but the resulting
mailbox will probably be called something like
/users/nirmala/old/na�ve (instead of …/naïve). The
mailbox names can be repaired using any IMAP client.

If the mail isn't on the same host that will run the database, then
it's best to run aoximport where the old mail is, and have it connect
to the mail database via TCP.

To do this, you need to compile Archiveopteryx, but make
install isn't necessary. Then you copy
archiveopteryx.conf from the target
server. aoximport will read the archiveopteryx.conf, find
db-address etc., and write the mail
to the right database via TCP.